Allow ConfigParser or a io.IO[Any] on log_config

[antonymayi]

This is a new instance of PR #1716 closed accidentally by deleting the forked repository.

Copy of the previous description:

The existing logic for the log_config option accepts:

• dict or str representing a JSON or YAML file name to be parsed using logging.config.dictConfig
• str representing an INI file name to be parsed using logging.config.fileConfig

The logging.config.fileConfig, however, accepts not only the file name, but possibly also an instance of configparser.RawConfigParser and even an open file object. Passing the instance of configparser.RawConfigParser (or its subclass) would be especially useful as this can accumulate configs from multiple files (cp.read() can be called repeatedly on different files updating its config values) instead of just a single one.

I am proposing this trivial change to allow the log_config option to also accept the *ConfigParser instance or a general file object.

[karpetrosyan]

These two options, which are listed in the logging documentation, can help with project configuration management

Changed in version 3.4: An instance of a subclass of RawConfigParser is now accepted as a value for fname. This facilitates:

Use of a configuration file where logging configuration is just part of the overall application configuration.

Use of a configuration read from a file, and then modified by the using application (e.g. based on command-line parameters or other aspects of the runtime environment) before being passed to fileConfig.

I like how fileConfig is used in this way.